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R. J. GRAY Feb. 3, 1931.

GREASE GUN Filed April 20, 1929 INVENTOR RUSSELL :I GRAY aY 'ATroRNEY y l Patented Feb. 3, 1931 UNITED STATES PATENT oFI-IcE RUSSELL J. GRAY, or MINNEAPOLIS, MINNESOTA GREASE etna f 'Application 1aed April zo, 1929; serial No. 356,668.

grease gun, the majorportion being shown v 1n diamtrical section, and with the piston in the position assumed when the cylinder is empty of grease.

Fig. 2 is a diametrical Section of the gun and showing it as partly filled with grease.

Fig. 3 is a sectional elevation similar to Fig. 2, but Showing the piston in an advanced position.

Referring to the drawing more particularly and by reference characters, 4 designates a cylinder in whichoperates a piston 5. The piston 5 is secured to one end of a sleeve 6, the opposite end of which is slidably mounted on a rod 7 that extends through a cap 8, ofthe cylinder 4, to a handle 9 having a knob portion 10. The cap 8 has a spring depressed pin 11 that normally rests against the bar 7 but when the sleeve 6 is pulled back its tapered end 12 moves/the pin up, or out, until it can drop into an annular groove 13 in the sleeve. The piston` 5 is normally pressed forward, i. e., away from the cap 8, by a spring 14, and this sprin must of course be compressed when the piston is to be pulled back for locking engagement with the pin 11. The pin 11 is provided with a button head 15 bywhich it may be released to permit the piston to move forward. The forward end of the bar or rod 7 is provided with an integral collar 16, for stopping eigagement with the Sleeve 6, and has a rigi forwardlyextending pin 'or linger portion 17 that serves as and may be conventiently designated as a plunger. The forward end of the plunger 17 is ointed or tapered, as at 18, so that it will etter sunk axial opening or chamber of a barrel 1'9, which barrel lis detachably secured to the cylinder 4 by a trunco-conical collar 20. The barrel 19 has a check valve 21 at its forward end," and terminates in a connector nipple 22 for convenient connection vto the fitting of the bearing or other element to be lubricated.

The operation of the, device may be briefly described as follows: To load the grease gun the barrel 19 is unscrewed from the collar is thus provided with a large opening at its front end, and the front end of the cylinder is then emerged in a supply of grease, and is preferably held in one hand while the other hand of the operator grasps. the handle 19 and pulls it'away from the cylinder. By so doing the collar 16 engages the sleeve 6, and pulls the piston 5 back until the pin 11 is snapped into locking engagement with the annular groove 13 of the collar. In this ,manner the cylinder is filled with grease, and

the piston is locked so that the spring 14 cannot push it forward until after the barrel 19 has again been attached to the cylinder. At this time the operator grasps the button 15 fand by giving it a short pull releases the pin 11 from the sleeve 6', and thus permits the pressure of the Spring 14 to act on the piston `5. The spring of the check valve 21 has Suficient tension to hold the valve closed against the action of the spring 14, so that no leakage will occur. When a bearing or other part having the necessary fitting is now to 'be lubricated the connector 22 is applied to the lit- 20, or the collar 2() may be unscrewed from l the cylinder` 4. In either event the cylinder ting and the operator then pushes the rod 7 forward until thefplunger 17 enters the barrel 19.- This action.. shuts the barrel b19 off from communication with the cylinder, and leaves acharge of lgrease in the barrel. TheA operator then gives the knob 10 a blow or substantial lpush with his hand, which action forces the charge of grease in the barrel 19 through the valve 21 and out through the connector 22 to the fitting, as indicated in Fig. 3. The handle 9 is now pulled back until the barrel 19 is again open to the cylinder 4, upon which the piston 5, under the kac ti'on of pel the excessivec'harges of grease that have the barrel 19 fiom the supply of lubricant inv the cylinder 4.l The operation is then repeated in the manner previously noted to exbeen fed to the barret 19.

llt may here be stated that the reasonl for providing the piston 5 with the sleeve 6, into which the collar 16and plunger 17 are drawn, as'shown in Fig. 2, is that this construction permits the piston 5 to be advanced` the full length' of the cylinder 4, so that practically7 all of the grease in the cylinder can be utilized before it is again necessary to refill it. There is, of course, suflicient clearance between the collar 16 and the inner periphery ofthe sleeve 6 to permit the collar'to be 4drawn into the'sleeve, as shown.

It is understood that suitable modifications may be made in the structure as disclosed, provided such modifications come within lthe spirit and scope of the appended claims..

Having now therefore fully illustrated and v described my invention what I claim to be new and desireto protect by Letters Patent grease guncomprising a'cylinder, an

ejector arre1`at one end of the cylinder, a

piston in the cylinder, a spring urgin the iston `toward the ejector barrel, a s eeve aving -an open end securedv to the (piston and having its other end closed, a ro slidable'in the closed end of the sleeve and through one end of the c linder, a vstop member carried by the rod, or engagement with the closed end of the sleeve, a lunger car'- riedb the inner end of the ro for enga ment -1n the ejector barrel, said plunger ecarried by the piston, said sleeve dayof April, 1929.

ing movable into the piston sleeve so as to' permit a maximum advance movement of the piston in the cylinder.

2. A ease gun comprising a cylinder, an lejector arrel at one end of the cylinder, a

piston inthe cylinder, a spring urgin the piston toward the ejector barrel a s eeve having an open end and one closed end, a rod slidable in the sleeve and through one end of the cylinder, a alungcr carried by the inner end of the rod or engagement in the ejector barrel, said plunger having freedom for passage into the piston sleeve through the open end there of so as to permit amaximum advance movement of the piston in the c linder, and a stop v member carried by the' ro and-movable intoA the sleeve with the plunger so as to stop against the closed end of the sleeve.

Signed t Minneapolis, in the countyof. Hennepin, and State .1.' can. 

